Streamlined Reheat Burner Fuel Lance for Low Pressure Drop
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Solution Overview
Problem
Current gas turbines with sequential combustion systems face challenges in achieving high efficiency while minimizing NOx emissions and life cycle costs, particularly when operating under high reactivity conditions or burning fuels with high calorific values like MBtu fuels, due to issues with fuel distribution and pressure loss in secondary burners.
Innovation Solution
The design of a secondary burner with inline fuel injection and a streamlined body structure that includes a longitudinal inner fuel tubing and branching off tubing, combined with vortex generators, allows for reduced pressure loss and enhanced mixing, enabling the use of lower pressure carrier air and eliminating the need for high-pressure fuel injection, thereby reducing NOx emissions and operational costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fuel is injected at the trailing edge of the nozzle to penetrate into vortices, then mixing quality is improved, but pressure loss increases and auto-ignition risk increases
Solution Approach 1:
The fuel injection point is positioned downstream of the trailing edge, allowing the fuel to be injected after the main flow has already established its vortex structure. This preliminary positioning of the injection point relative to the flow development stage allows the fuel to penetrate into the vortices without requiring excessive injection momentum, thereby reducing pressure loss while maintaining mixing quality.
Solution Approach 2:
The invention changes the spatial parameter of fuel injection location from the trailing edge position to a downstream position. This parameter change allows the fuel to utilize the already-formed vortex structure rather than对抗 it, reducing the momentum flux requirement and associated pressure losses while maintaining effective mixing.
2Manufacturing precision
If fuel injection pressure is increased to ensure proper distribution, then fuel distribution is improved, but pressure loss increases and hardware complexity increases
Solution Approach 1:
The streamlined body and vortex generators create the flow structure and mixing environment in advance, before fuel injection occurs. This preliminary flow conditioning eliminates the need for high fuel injection pressures to achieve proper distribution, as the pre-formed vortices naturally draw fuel into the mixing zone.
Solution Approach 2:
The invention introduces vortex generators and a streamlined body as intermediary elements between the fuel injection system and the combustion chamber. These intermediaries prepare the oxidizer flow in advance, creating a receptive environment that reduces the pressure requirements for fuel distribution.
3Manufacturing precision
If residence time in mixing region is extended to improve mixing, then mixing quality is improved, but auto-ignition risk increases
Solution Approach 1:
The invention changes the flow velocity parameter through the streamlined body design and vortex generator configuration. By optimizing the velocity field, the mixing process occurs rapidly enough to achieve quality mixing without extending the residence time beyond the auto-ignition delay threshold.
Solution Approach 2:
Vortex generators create controlled turbulent structures that enhance mixing through rotational motion and chaotic flow patterns. This mechanical mixing action achieves thorough fuel-oxidizer blending in a shorter time frame compared to laminar mixing, preventing auto-ignition in the mixing zone.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design achieves a significant reduction in fuel pressure drop, enabling efficient combustion of high reactivity fuels with lower emissions and reduced hardware costs by eliminating the need for high-pressure fuel compression, while maintaining the overall efficiency of the process.
Implementation Method 1
upstream of the at least one nozzle at least one vortex generator is located
Implementation Method 2
there is provided a longitudinal inner fuel tubing element for the introduction of liquid and/or gaseous fuel, with branching off tubing, essentially extending parallel to the direction of the main flow direction, leading to the at least one nozzle for the delivery of fuel
Implementation Method 3
the subsequent mixing of the fuel and the oxidizer at the exit of the mixing zone
Implementation Method 4
a part of the fuel is combusted
Data Source
Figure 1~2b
Figure 3a~3i
Figure 3e~3h
AI summary
The invention relates to a burner (1) preferably for a secondary combustion chamber of a gas turbine with sequential combustion having a first and a second combustion chamber, with an injection device (7) for the introduction of at least one gaseous and/or liquid fuel into the burner (1), wherein the injection device (7) has at least one body (22) which is arranged in the burner (1) with at least one nozzle (15) for introducing the at least one gaseous fuel into the burner (1), the at least one body being configured as a streamlined body (22) which has a streamlined cross-sectional profile (48) and which extends with a longitudinal direction (49) perpendicularly or at an inclination to a main flow direction (14) prevailing in the burner (1), wherein the body (22) has two lateral surfaces (33) essentially parallel to the main flow direction (14). Low fuel pressure drop reheat injection is possible according to the invention is the at least one nozzle (15) having its outlet orifice downstream of a trailing edge (24) of the streamlined body (22).